Question

I have a product table:

Product
- PId
- Name

ProductPricing
- PPId
- PId
- startDate
- endDate
- price

For one product, there can be multiple ProductPricing records.

For retrieving current price for the product, I use the following query:

SELECT PId, Name, price, startDate, endDate
FROM PRODUCT, PRODUCTPRICING
WHERE PRODUCT.PId = givenId AND PRODUCT.PId = PRODUCTPRICING.PId
AND (today() > PRODUCTPRICING.startDate AND today() < PRODUCTPRICING.endDate);

How do I map the result of this query to my POJO using Hibernate ??

my Java Product object looks something like this:

Product
- Id
- Name
- ProductPricing Object

ProductPricing
- startDate
- endDate
- price

Answer 1

This will give a slightly different query (with a sub-query instead of a join), but the result should be the same.

@Entity
class Product
{
@Id
int id;
String name;
@Formula("(select pp.price from PRODUCTPRICING pp where pp.PId = id and today() > pp.startDate AND today() < pp.endDate )")
double price;
}

If you want to map the ProductPricing as a POJO, too, I think you can’t map it as a one-to-one, since it’s technically a one-to-many with a filter which will hopefully result in only one result. So you’ll have a Set<ProductPricing> in your Product class:

<set name="prices" table="PRODUCTPRICING">
  <key column="PId"/>
  <composite-element class="ProductPricing">
    <property name="price"/>
    <property name="startdata"/>
    <property name="enddate"/>
  </composite-element>
  <filter condition="today() > startDate AND today() < endDate"/>
</set>

With composite-element, you don’t need a primary key PPId in the PRODUCTPRICING table.